Medium-voltage (e.g., greater than 1500 volts) power electronics assemblies, such as adjustable speed drives, often use groups of power transistors and diodes switched on and off in a predetermined timing sequence to supply the level and frequency of power desired. Because of the high voltage levels in which they operate (e.g., 2400 volts, 3300 volts, 4160 volts, 6600 volts, etc.), and the associated levels of current, these devices tend to generate significant amounts of excess heat.
It is desirable to dissipate the excess heat generated by such medium-voltage drives throughout their operation. Known methods for dissipating the excess heat involve using a fan to draw air through the cabinet housing the power devices of the medium-voltage drive. Doing so, however, results in airborne contaminants being deposited on the power devices such that, over time, the devices will require maintenance and/or cleaning. The contaminants may also interfere with the operation of the devices, or may cause even more heat to build up (e.g., as the contaminants may tend to trap heat) and reduce the lifespan of the devices. Controlling the operating environment of the power devices becomes even more complicated when the medium-voltage drives are housed in outdoor units and exposed to extreme cold ambient conditions.